Choosing the Right Size Replacement Blind Slats

When ordering replacement vertical blind slats, choosing the correct width is essential.

Most vertical blinds in the UK use one of two standard slat sizes:

• 89mm (3.5 inch) slats
• 127mm (5 inch) slats

If you’re unsure which size you need, this simple guide will help you identify the correct option and choose what works best for your space.

Quick Answer – Which Size Do I Need?

• ✔ 89mm slats → Most common choice for UK homes
• ✔ 127mm slats → Used for larger windows and doors

The easiest way to confirm is to measure the width of one existing slat.

89mm Vertical Blind Slats

✅ The most popular option

89mm slats are the standard size used in most domestic properties.

Best for:

• Living rooms
• Bedrooms
• Offices
• Standard windows

Benefits of 89mm slats:

• More slats across the window → finer, neater appearance
• Better light control
• Works well in smaller sized windows
• Widely compatible with most existing blind systems

When to choose 89mm:

If your existing slats measure around 89mm wide, or you want a more refined, traditional look, this is the right option.

---

Shop 89mm Slats:

[Shop 89mm Replacement Slats]

127mm Vertical Blind Slats

✅ Wider slats for larger spaces

127mm slats are ideal for bigger openings where fewer, wider slats create a cleaner look.

Best for:

• Patio doors
• Bi-fold doors
• Large windows
• Conservatories

Benefits of 127mm slats:

• Fewer slats → less visual clutter
• More open feel when blinds are drawn
• Better suited to large glass areas
• Contemporary appearance

When to choose 127mm:

If your existing slats measure around 127mm wide, or you have a large window or door area, this size is typically the best fit. 

Shop 127mm Slats:

[Shop 127mm Replacement Slats]

How to Measure Your Slats

Measuring is quick and simple:

1. Remove one existing slat
2. Measure the width across the top
3. Match it to either:
   • 89mm
   • 127mm

The measurement should be very close to one of these standard sizes.

✅ Important:

• Do not measure the whole blind
• Only measure the width of a single slat

Can I Change Slat Size?

In most cases, No – you must match your existing size

Your blind headrail is designed to work with one specific slat width. However it is possible to replace vanes on a 89mm spaced track with 127mm slats to provide increased overlap if required.

Mixing sizes will not fit correctly.

Still Not Sure?

If you’re unsure which size you need:

• ✔ Measure an existing slat
• ✔ Compare with this guide
• ✔ Or contact us for help

We’re always happy to help you choose the correct replacement slats.

Ready to Choose Your Size?

[Shop All 89mm Slats]

[Shop All 127mm Slats]